http://www.rfc-editor.org/rfc/rfc7903.txt
RFC 7903: Windows Image Media Types, S. Leonard2016-09-01T23:00:00-00:00This document registers media types for certain image formats promulgated in Microsoft Windows, namely image/wmf, image/x-wmf, image/emf, image/x-emf, and image/bmp for use with Windows Metafile, Enhanced Metafile, and Windows Bitmap formats. Originally designed for Microsoft Windows 2.0 and 3.0, these image files are intended to be portable between applications and devices, and they may contain both vector and raster graphics.